939 research outputs found
INFLUENCE OF AGING ON THE DYNAMICS OF LATERAL STABILIZATION IN WALKING, IN DIFFERENT EXPERIHENTAL CONDITIONS RELATED TO SHOE WEARING AND FLOOR HARDNESS
Review of biomechanics literature on the influence of aging on the locomotor system indicates that safe load bearing as well as deformation sustaining capabilities of biological tissues decrease with age. Postural studies of older
populations have di8closed more body sway than in younger age groups and have often associated loss of balance with locomotion problems of old age people. On the other hand, biomechanical studies of walking and running have already demonstrated t h a t wearing shoes and shoe characteristics can play an important r o l e in shock absorption. However the influence of aging on the dynamic of lateral stabilization in walking in relationship with shoe wearing and floor hardness has received very little attention. Such a biomechanical approach t o locomotion is becoming more important since more and more older people are involved in sport and fitness activities including some form of locomotion. The present study has been undertaken in order to investigate the influence of aging together with shoe wearing and floor hardness on some of the main components, of lateral stabilization in walking, namely the lateral forces, the lateral impulse and the lateral deviation o f the center of pressure. Three groups of 15 physically active male subjects (17-22, 40-45 and 65-70 years old) were instructed to walk on a tri-dimensional force platform a t a predetermined pace set with a metronome;. Experimental conditions included walking barefoot and with regular shoes, on a hard and a softer surfaces. Kinetic data were recorded on the 5th, 25th, 50th, 100th and 500th steps for each condition, with the use of the computerized . Ariel Performance Analysis System. Analysis of the results disclosed important differences between the age groups in all three experimental parameters. Lower lateral forces exerted by the older age group lead t o the hypothesis of a different stabilization strategy based on energy saving. Findings were also discussed in relationship with the lateral stabilization process and applications were made to sport and fitness activities a s well a s the daily living situations
Transition from Diffusive to Localized Regimes in Surface Corrugated Optical Waveguides
Exact calculations of the transmittance of surface corrugated optical
waveguides are presented. The elastic scattering of diffuse light or other
electromagnetic waves from a rough surface induces a diffusive transport along
the waveguide axis. As the length of the corrugated part of the waveguide
increases, a transition from the diffusive to the localized regime is observed.
This involves an analogy with electron conduction in nanowires, and hence, a
concept analogous to that of ``resistance'' can be introduced. We show an
oscillatory behavior of both the elastic mean free path and the localization
length versus the wavelength.Comment: 3 pages, REVTEX, 3 PS figure
Photonic integrated reconfigurable linear processors as neural network accelerators
Reconfigurable linear optical processors can be used to perform linear transformations and are instrumental in effectively computing matrixâvector multiplications required in each neural network layer. In this paper, we characterize and compare two thermally tuned photonic integrated processors realized in silicon-on-insulator and silicon nitride platforms suited for extracting feature maps in convolutional neural networks. The reduction in bit resolution when crossing the processor is mainly due to optical losses, in the range 2.3â3.3 for the silicon-on-insulator chip and in the range 1.3â2.4 for the silicon nitride chip. However, the lower extinction ratio of MachâZehnder elements in the latter platform limits their expressivity (i.e., the capacity to implement any transformation) to 75%, compared to 97% of the former. Finally, the silicon-on-insulator processor outperforms the silicon nitride one in terms of footprint and energy efficiency
The Empirical Power of Rare Variant Association Methods: Results from Sanger Sequencing in 1,998 Individuals
The role of rare genetic variation in the etiology of complex disease remains unclear. However, the development of next-generation sequencing technologies offers the experimental opportunity to address this question. Several novel statistical methodologies have been recently proposed to assess the contribution of rare variation to complex disease etiology. Nevertheless, no empirical estimates comparing their relative power are available. We therefore assessed the parameters that influence their statistical power in 1,998 individuals Sanger-sequenced at seven genes by modeling different distributions of effect, proportions of causal variants, and direction of the associations (deleterious, protective, or both) in simulated continuous trait and case/control phenotypes. Our results demonstrate that the power of recently proposed statistical methods depend strongly on the underlying hypotheses concerning the relationship of phenotypes with each of these three factors. No method demonstrates consistently acceptable power despite this large sample size, and the performance of each method depends upon the underlying assumption of the relationship between rare variants and complex traits. Sensitivity analyses are therefore recommended to compare the stability of the results arising from different methods, and promising results should be replicated using the same method in an independent sample. These findings provide guidance in the analysis and interpretation of the role of rare base-pair variation in the etiology of complex traits and diseases
Evaluation of knowledge level of adolescents and adults with congenital heart disease: Effectiveness of a structured CHD education program in adolescents
BackgroundAdolescents with congenital heart disease (CHD) constitute a growing population of individuals for whom a well-planned and well-executed âtransition processâ is essential. Transition program should include education about medical conditions and promote skills in decision-making and self-care. To improve their level of health related knowledge, a structured education program was implemented in a transition CHD program. This study aimed 1/to evaluate level of knowledge of adolescents who received structured CHD education as compared to adults who did not, 2/to evaluate whether patients who received structured education improve their knowledge.Methods and results42 adolescents (16±2years old, 21 girls) were included in a structured CHD education program and were compared to 22 adults (33±7, 6 women) with CHD who have never followed education program. Knowledge in adolescents was assessed before and after the educational program using questionnaire exploring specific issues related to CHD. A same questionnaire was used in non-educated adult patients. The mean total knowledge score in the educated adolescent group was significantly higher as compared to the non-educated adult with CHD (score=15.6/20±3.6 vs. 12.5±4.5, P<0.01). Provision of structured CHD education and female sex were determinant of higher levels of knowledge. A significant improvement of knowledge was observed in adolescents group after CHD education program (range of increase was 23 to 44%). This result was not influenced by age, sex, education level, socio-economic status of parents and disease complexity, and persists at 10months mean follow-up.ConclusionA structured education program was associated with a higher level of knowledge, above all in male CHD patients. Education at transition period has a significant impact on the adolescent knowledge. Structured education program should improve adult CHD understanding of their heart condition, and could prevent potential complications
The recovery of plant community composition following passive restoration across spatial scales
Human impacts have led to dramatic biodiversity change which can be highly scale-dependent across space and time. A primary means to manage these changes is via passive (here, the removal of disturbance) or active (management interventions) ecological restoration. The recovery of biodiversity, following the removal of disturbance, is often incomplete relative to some kind of reference target. The magnitude of recovery of ecological systems following disturbance depends on the landscape matrix and many contingent factors. Inferences about recovery after disturbance and biodiversity change depend on the temporal and spatial scales at which biodiversity is measured. We measured the recovery of biodiversity and species composition over 33 years in 17 temperate grasslands abandoned after agriculture at different points in time, collectively forming a chronosequence since abandonment from 1 to 80 years. We compare these abandoned sites with known agricultural land-use histories to never-disturbed sites as relative benchmarks. We specifically measured aspects of diversity at the local plot-scale (α-scale, 0.5 m2) and site-scale (Îł-scale, 10 m2), as well as the within-site heterogeneity (ÎČ-diversity) and among-site variation in species composition (turnover and nestedness). At our α-scale, sites recovering after agricultural abandonment only had 70% of the plant species richness (and ~30% of the evenness), compared to never-ploughed sites. Within-site ÎČ-diversity recovered following agricultural abandonment to around 90% after 80 years. This effect, however, was not enough to lead to recovery at our Îł-scale. Richness in recovering sites was ~65% of that in remnant never-ploughed sites. The presence of species characteristic of the never-disturbed sites increased in the recovering sites through time. Forb and legume cover declines in years since abandonment, relative to graminoid cover across sites. Synthesis. We found that, during the 80 years after agricultural abandonment, old fields did not recover to the level of biodiversity in remnant never-ploughed sites at any scale. ÎČ-diversity recovered more than α-scale or Îł-scale. Plant species composition recovered, but not completely, over time, and some species groups increased their cover more than others. Patterns of ecological recovery in degraded ecosystems across space and long time-scales can inform targeted active restoration interventions and perhaps, lead to better outcomes
Observational Study Design in Veterinary Pathology, Part 1: Study Design
Observational studies are the basis for much of our knowledge of veterinary pathology and are highly relevant to the daily practice of pathology. However, recommendations for conducting pathology-based observational studies are not readily available. In part 1 of this series, we offer advice on planning and conducting an observational study with examples from the veterinary pathology literature. Investigators should recognize the importance of creativity, insight, and innovation in devising studies that solve problems and fill important gaps in knowledge. Studies should focus on specific and testable hypotheses, questions, or objectives. The methodology is developed to support these goals. We consider the merits and limitations of different types of analytic and descriptive studies, as well as of prospective vs retrospective enrollment. Investigators should define clear inclusion and exclusion criteria and select adequate numbers of study subjects, including careful selection of the most appropriate controls. Studies of causality must consider the temporal relationships between variables and the advantages of measuring incident cases rather than prevalent cases. Investigators must consider unique aspects of studies based on archived laboratory case material and take particular care to consider and mitigate the potential for selection bias and information bias. We close by discussing approaches to adding value and impact to observational studies. Part 2 of the series focuses on methodology and validation of methods
Differentiating normal and problem gambling: a grounded theory approach.
A previous study (Ricketts & Macaskill, 2003) delineated a theory of problem gambling based on the experiences of treatment seeking male gamblers and allowed predictions to be made regarding the processes that differentiate between normal and problem gamblers. These predictions are the focus of the present study, which also utilised a grounded theory approach, but with a sample of male high frequency normal gamblers. The findings suggest that there are common aspects of gambling associated with arousal and a sense of achievement. The use of gambling to manage negative emotional states differentiated normal and problem gambling. Perceived self-efficacy , emotion management skills and perceived likelihood of winning money back were intervening variables differentiating problem and normal gamblers.</p
Thelazia rhodesii in the African Buffalo, Syncerus caffer, in Zambia
We report 2 cases of Thelazia rhodesii infection in the African buffaloes, Syncerus caffer, in Zambia. African buffalo calves were captured from the livestock and wildlife interface area of the Kafue basin in the dry season of August 2005 for the purpose to translocate to game ranches. At capture, calves (n=48) were examined for the presence of eye infections by gently manipulating the orbital membranes to check for eye-worms in the conjunctival sacs and corneal surfaces. Two (4.3%) were infected and the mean infection burden per infected eye was 5.3 worms (n=3). The mean length of the worms was 16.4 mm (95% CI; 14.7-18.2 mm) and the diameter 0.41 mm (95% CI; 0.38-0.45 mm). The surface cuticle was made of transverse striations which gave the worms a characteristic serrated appearance. Although the calves showed signs of kerato-conjunctivitis, the major pathological change observed was corneal opacity. The calves were kept in quarantine and were examined thrice at 30 days interval. At each interval, they were treated with 200 ”g/kg ivermectin, and then translocated to game ranches. Given that the disease has been reported in cattle and Kafue lechwe (Kobus lechwe kafuensis) in the area, there is a need for a comprehensive study which aims at determining the disease dynamics and transmission patterns of thelaziasis between wildlife and livestock in the Kafue basin
An analysis of consumer protection for gamblers across different online gambling operators in Ireland: a descriptive study
The aim of the present study was to evaluate the responsible gambling tools which are available to online gamblers at Irish online gambling websites. The present study used a similar methodology to a recent study carried out on the worldâs most popular websites (Bonello and Griffiths Gaming Law Review and Economics, 21, 278â285, 2017), where 50 of the most advertised online gambling websites were evaluated in relation to their responsible gambling (RG) practices. The present study evaluated 39 gambling websites with either a â.ieâ or â.com/ieâ domain. Each website was evaluated by checking for a number of RG practices, including presence of a dedicated RG page; age verification; access to gambling account history; the availability of RG tools, such as limit setting facilities and exclusion settings; and links to limit-setting options on the deposit page. Descriptive statistics were then performed on the results from each website. Of the 39 online gambling operators identified, 22 redirected gamblers to a â.comâ domain, while 17 operators remained as a â.ieâ domain. Thirty-five websites (89.7%) visited had a dedicated RG page. Responsible gambling features were evaluated and demonstrated to be available in an inconsistent manner across online gambling websites. Irish websites were shown to perform poorly in comparison with non-Irish counterparts in the provision of RG tools. The researchers of the present study are not aware of any similar studies conducted to date in Ireland
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